Biological Constraints

   The premise of equipotentiality states that the selection of the species, stimulus, response, reinforcer, and other aspects of the experimental preparation is arbitrary. A considerable amount of evidence now challenges this concept. As early as 1970, Seligman argued that the dimension of preparedness must be included in the analysis of conditioning. Preparedness refers to the idea that innate predispositions determine the conditionability of any two events. Biological predispositions apparently do determine what types of associations can be learned. Biological determinants of behavior may intrude on the learning process. The problems faced by the Brelands did not result from any difficulty in forming new associations. Rather, existing associations prevented new connections from being established. The existing behaviors are part of the animal's natural response profile, and the intrusion of such innate responses in a learning situation is called instinctive drift. In such cases, the animal's performance drifts away from the reinforced behaviors toward instinctive behaviors. These findings suggest that there are limits to classical conditioning and instrumental learning.